How to successfully use the adhoc group functionality in the Match Exception Collaboration Center?

Our company is looking for guidance on how other companies are using the adhoc group functionality in the Match Exception Collaboration Center. Currently, we have been rolling out the MECC in phase to our production environment and have a large group going that would like to use the adhoc group functionality, however we have found that when AP_Match process runs it overwrites the assignment with the match exception group assigned to the rule.

We have tried using the match exception group as much as possible, because we find it gives us the most value to assign rules to the user/groups that can affect the change to resolve the match exception. However, the match exception doesn't necessary stay with that group or user we expected to be able to adhoc a user or group to move the assignment when necessary. In doing so we are finding that the AP_MATCH process is reassigning the adhoc group assignments back to the match exception group the rule is auto assigned to.